Method and system for controlling electric water pump

ABSTRACT

A method of controlling an EWP through an EWP controller configured to communicate with an engine electronic control unit (ECU) on a controller area network (CAN) includes receiving a CAN signal from the ECU to control the EWP through the CAN; receiving a fail-safe digital signal (FSDS) that is related to a fail-safe control function of an engine or the EWP from the ECU; and controlling the EWP based on the CAN signal and the fail-safe digital signal.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to Korean PatentApplication No. 10-2014-0136124 filed in the Korean IntellectualProperty Office on Oct. 8, 2014, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a method and system for controlling anelectric water pump (EWP), and more particularly, to a method and systemfor controlling an electric water pump that may be effectivelycontrolled by separating a control signal for operation of the electricwater pump from a power signal and by using a digital signal outputtedfrom an engine electronic control unit (ECU).

BACKGROUND

As is well-known to a person of an ordinary skill in the art, an EWP isa pump that is independently operated or driven by a motor withoutdepending on power of an engine, while a mechanical water pump dependson power of an engine.

Since the EWP is independently controlled to supply a coolant flow ratesuitable for a driving condition of an engine or a vehicle regardless ofoperation of the engine, the EWP has the following merits.

First, since it is not needed for the EWP to operate during an initialoperating period of an engine, the engine can be rapidly warmed.

Second, a ratio of power of the EWP to power of a mechanical water pumpmay be about 60-70%.

Third, since the EWP is operated by power of a motor, a cooling systemof a vehicle may be compacted.

However, according to the related art, since the EWP is controlledthrough only ignition (IG) power and a controller area network (CAN)signal outputted from an ECU, the EWP operates only in a limp-home modewhen the CAN signal is unstable.

In other words, according to the conventional EWP control method, whenthe EWP operates abnormally, the EWP may not be effectively used.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the invention andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

RELATED ART DOCUMENTS Patent Documents

(Patent Document 1) Patent Laid-Open Publication No. KR 10-2008-0035263(Apr. 23, 2008)

(Patent Document 2) Patent Laid-Open Publication No. KR 10-2012-0140412(Dec. 31, 2012)

SUMMARY

Accordingly, the present disclosure has been made in an effort toprovide a method and system for controlling an EWP that may effectivelyperform fail-safe control and driving control for the EWP by separatinga control signal for operation of the EWP from a power signal and byusing a digital signal outputted from an ECU.

For this purpose, an exemplary embodiment of the present inventionprovides a method of controlling an EWP through an EWP controllerconfigured to communicate with an ECU on a controller area network(CAN). The method may include: receiving a CAN signal from the ECU tocontrol the EWP through the CAN; receiving a fail-safe digital signal(FSDS) that is related to a fail-safe control function of an engine orthe EWP from the ECU; and controlling the EWP based on the CAN signaland the fail-safe digital signal.

In certain embodiments, the EWP may include an auxiliary EWP which coolsa heater, a turbocharger, and an inverter. In certain embodiments, themethod may further include detecting battery power that is supplied tothe EWP by a battery or ignition (IG) power that is supplied to the EWPby an IG power portion.

In certain embodiments, the method may further include receiving arotation speed command for the EWP from the ECU through the CAN.

In certain embodiments, when the IG power is turned on and the CANsignal is normal, the EWP may be controlled based on commands from theECU.

In certain embodiments, when the IG power is turned on and the FSDS isnormally inputted to the EWP controller while the CAN signal is notinputted to the EWP controller, the EWP may be controlled in thelimp-home mode.

In certain embodiments, when the IG power is turned on and the FSDS isnot normally inputted to the EWP controller while the CAN signal is notinputted to the EWP controller, the EWP may be controlled in the wake-upmode.

In certain embodiments, when the IG power is turned off and the CANsignal is normally inputted to the EWP controller, the EWP may becontrolled based on commands from the ECU, and when the IG power isturned off and the CAN signal is not normally inputted to the EWPcontroller, the EWP may be set to enter a sleep mode.

In certain embodiments, when the EWP is set to enter the sleep mode fromthe normal mode, the sleep mode may be performed after a predeterminedtime has passed.

Another embodiment of the present invention provides a system forcontrolling an EWP, including: an ECU configured to control an engine;an EWP configured to cool the engine; a battery configured to supply theEWP with battery power (B+); an ignition power portion configured tosupply the EWP with ignition (IG) power. An EWP controller is configuredto communicate with the ECU on a controller area network (CAN), receivea CAN signal from the ECU to control the EWP through the CAN, receive afail-safe digital signal (FSDS) from the ECU, and control the EWP basedon the CAN signal and the FSDS.

In certain embodiments, the EWP may include an auxiliary EWP which coolsa heater, a turbocharger, and an inverter. In certain embodiments, theEWP controller may be further configured to detect the battery powerthat is supplied to the EWP by the battery or the IG power supplied bythe IG power portion. In certain embodiments, the EWP controller may befurther configured to receive a rotation speed command for the EWP fromthe ECU through the CAN.

Another embodiment provides a computer readable storage mediumcontaining a computer program configured to cause an EWP controller tocontrol an electric water pump (EWP) by the following method when readand processed by a computer system: receiving a controller area network(CAN) signal from an engine electronic control unit (ECU) to control theEWP through a controller area network (CAN); receiving a fail-safedigital signal (FSDS) that is related to a fail-safe control function ofan engine or the EWP from the ECU; and controlling the EWP based on theCAN signal and the fail-safe digital signal.

As described above, according to an embodiment of the present invention,the method and system for controlling an EWP can be provided toeffectively control the EWP by separating a control signal for the EWPfrom a power signal and by using a digital signal outputted from theECU.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for controlling the EWP accordingto an exemplary embodiment of the present invention.

FIG. 2 is a flowchart of a method of controlling the EWP according to anexemplary embodiment of the present invention.

FIG. 3 is a condition table related to control modes of the EWPaccording to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention will be described more fullyhereinafter with reference to the accompanying drawings, in whichexemplary embodiments of the invention are shown. As those skilled inthe art would realize, the described embodiments may be modified invarious different ways, all without departing from the spirit or scopeof the present invention.

In addition, in the specification, unless explicitly described to thecontrary, the word “comprise” and variations such as “comprises” or“comprising” will be understood to imply the inclusion of statedelements but not the exclusion of any other elements.

FIG. 1 is a block diagram of a system for controlling the EWP accordingto an exemplary embodiment of the present invention.

The system for controlling the EWP according to an exemplary embodimentof the present invention may control the EWP by separating a controlsignal for operation of the EWP from a power signal, and by using adigital signal outputted from the ECU.

A system for controlling the EWP according to an exemplary embodiment ofthe present invention includes: an ECU 100 configured to control anengine 1; an EWP 30 configured to cool the engine 1; a battery 10configured to supply the EWP 30 with battery power (B+); an ignitionpower portion 20 configured to supply the EWP 30 with ignition (IG)power; and an EWP controller 200 configured to communicate with the ECU100 on a controller area network

(CAN). The EWP controller may be configured to receive a CAN signal fromthe ECU to control the EWP through the CAN, receive a fail-safe digitalsignal (FSDS) from the ECU, and control the EWP based on the CAN signaland the FSDS. In certain embodiments, the EWP controller is furtherconfigured to perform a normal mode, a limp-home mode, a sleep mode, anda wake-up mode, to receive a fail-safe digital signal (FSDS) from theECU 100, and to perform fail-safe control and driving control for theEWP 30. The EWP controller may also perform other control functions ofthe EWP. The EWP 30 may include an auxiliary EWP (not shown) which coolsa heater, a turbocharger, and an inverter.

The battery power and the ignition (IG) power may be directly suppliedto the EWP 30 from the battery 10 and the IG power portion 20 as powersfor driving the EWP 30.

The battery power and the ignition (IG) power are supplied to the EWPcontroller 200, and the EWP controller 200 detects the powers that aresupplied to the EWP 30 from the battery 10 and the IG power portion 20.

The EWP controller 200 may receive a command such as a rotation speedcommand for the EWP 30, and various kinds of commands through the CANfrom the ECU 100.

In the exemplary embodiment of the present invention, the engine 1, thebattery 10, the IG power portion 20, and the EWP 30 may be thosetypically applied in the related art, so the detailed descriptionsthereof will be omitted in the present specification.

The EWP controller 200 may include one or more processors ormicroprocessors, and/or hardware operated by a predetermined programincluding a series of commands for executing a method of controlling theEWP according to an exemplary embodiment of the present invention, whichwill be described below.

Hereinafter, a method of controlling the EWP according to an exemplaryembodiment of the present invention will be described in detail withreference to the accompanying drawings.

FIG. 2 is a flowchart of the method of controlling the EWP according toan exemplary embodiment of the present invention, and FIG. 3 is adrawing showing a condition table related to control modes of the EWPaccording to the exemplary embodiment of the present invention.

As shown in FIGS. 2 and 3, the EWP controller 200 determines whether theIG power is turned on, communication on the CAN is normal, and the FSDSsignal is inputted to the EWP controller 200.

In certain embodiments, when the IG power is turned on (S110) and theCAN signal is normal (S120), since the EWP controller 200 may controlthe EWP 30 regardless of the FSDS signal (S130), the EWP controller 200normally controls the EWP 30 based on commands for operation of the EWP30 outputted from the ECU 100 (S210).

In certain embodiments, when the CAN signal is abnormal as the CANsignal is interrupted at step S120 and the FSDS signal is normallyinputted to the EWP controller 200 (S125), the EWP controller 200controls the EWP 30 in the limp-home mode (S220). In other words, inthis case, even though the EWP 30 can be operated, since no normalcontrol signal exists due to an interruption of the CAN signal, thelimp-home mode is performed.

In certain embodiments, when the FSDS signal is off at step S125, sincethis case is a condition such as no normal CAN signal exists due to, forexample, cutting of a wire for the FSDS signal, the EWP controller 200controls the EWP 30 in the wake-up mode (S230).

In certain embodiments, when the IG power is turned off at step S110 andthe CAN signal is normally inputted to the EWP controller 200 (S150),this is a case of the CAN signal being normally received and transmittedto and from the EWP controller 200. Accordingly, regardless of the FSDSsignal (S160), the EWP controller 200 controls the EWP 30 in the normalmode based on the commands from the ECU 100 (S240).

In certain embodiments, when the CAN signal is not normally inputted tothe EWP controller 200 at step S150, this is a case of a control signalfor controlling the EWP 30 not existing. Accordingly, regardless of theFSDS signal (S155), the EWP controller 200 controls the EWP 30 in thesleep mode (S250).

Referring to FIG. 3, in certain embodiments, when an operation of theEWP 30 enters the sleep mode from the normal mode, the EWP controller200 performs the sleep mode after a predetermined time (e.g., about 15seconds) is passed. This is to prevent a problem of a hot spot occurringdue to stoppage of coolant flow in a cooling circuit of the vehicle whenthe EWP 30 is suddenly stopped, thereby causing a high temperature atthe hot spot. In other words, when the operation of the EWP 30 entersthe sleep mode, the EWP controller 200 may control the EWP 30 in thesleep mode after further operating the EWP 30 during the predeterminedtime (e.g., about 15 seconds). The predetermined time may be previouslyset and programmed, which is apparent to those skilled in the art.

Accordingly, accordingly to the exemplary embodiment of the presentinvention, the EWP may be effectively controlled by separating thecontrol signal for operation of the EWP from the power signal and byusing the digital signal outputted from the ECU.

While practical exemplary embodiments of this invention have beendescribed above, it is to be understood that the invention is notlimited to the disclosed embodiments, but, on the contrary, is intendedto cover various modifications and equivalent arrangements includedwithin the spirit and scope of the appended claims.

What is claimed is:
 1. A method of controlling an electric water pump(EWP) through an EWP controller configured to communicate with an engineelectronic control unit (ECU) on a controller area network (CAN), themethod comprising: receiving a CAN signal from the ECU to control theEWP through the CAN; receiving a fail-safe digital signal (FSDS) that isrelated to a fail-safe control function of an engine or the EWP from theECU; and controlling the EWP based on the CAN signal and the fail-safedigital signal.
 2. The method of claim 1, wherein the EWP comprises: anauxiliary EWP which cools a heater, a turbocharger, and an inverter. 3.The method of claim 1, further comprising: detecting battery power thatis supplied to the EWP by a battery or ignition (IG) power that issupplied to the EWP by an IG power portion.
 4. The method of claim 3,further comprising: receiving a rotation speed command for the EWP fromthe ECU through the CAN.
 5. The method of claim 4, further comprising:when the IG power is turned on and the CAN signal is normal, controllingthe EWP in a normal mode based on commands from the ECU.
 6. The methodof claim 4, further comprising: when the IG power is turned on and theFSDS is normally inputted to the EWP controller while the CAN signal isnot inputted to the EWP controller, controlling the EWP in a limp-homemode.
 7. The method of claim 4, further comprising: when the IG power isturned on and the FSDS is not normally inputted to the EWP controllerwhile the CAN signal is not inputted to the EWP controller, controllingthe EWP in a wake-up mode.
 8. The method of claim 4, further comprising:when the IG power is turned off and the CAN signal is normally inputtedto the EWP controller, controlling the EWP in a normal mode based oncommands from the ECU, and when the IG power is turned off and the CANsignal is not normally inputted to the EWP controller, setting the EWPto enter a sleep mode.
 9. The method of claim 8, further comprising:when the EWP is set to enter the sleep mode from the normal mode,performing the sleep mode after a predetermined time has passed.
 10. Asystem for controlling an electric water pump (EWP), comprising: anengine electronic control unit (ECU) configured to control an engine; anelectric water pump (EWP) configured to cool the engine; a batteryconfigured to supply the EWP with battery power; an ignition powerportion configured to supply the EWP with ignition (IG) power; and anEWP controller configured to communicate with the ECU on a controllerarea network (CAN), receive a CAN signal from the ECU to control the EWPthrough the CAN, receive a fail-safe digital signal (FSDS) from the ECU,and control the EWP based on the CAN signal and the FSDS.
 11. The systemof claim 10, wherein the EWP comprises: an auxiliary EWP which cools aheater, a turbocharger, and an inverter.
 12. The system of claim 10,wherein the EWP controller is further configured to detect the batterypower that is supplied to the EWP by the battery or the IG powersupplied by the IG power portion.
 13. The system of claim 12, whereinthe EWP controller is further configured to receive a rotation speedcommand for the EWP from the ECU through the CAN.
 14. The system ofclaim 13, wherein the EWP controller is further configured to controlthe EWP in a normal mode based on commands from the ECU when the IGpower is turned on and the CAN signal is normal.
 15. The system of claim13, wherein the EWP controller is further configured to control the EWPin a limp-home mode when the IG power is turned on and the FSDS isnormally inputted to the EWP controller while the CAN signal is notinputted to the EWP controller.
 16. The system of claim 13, wherein theEWP controller is further configured to control the EWP in a wake-upmode when the IG power is turned on and the FSDS is not normallyinputted to the EWP controller while the CAN signal is not inputted tothe EWP controller.
 17. The system of claim 13, wherein the EWPcontroller is further configured to control the EWP in a normal modewhen the IG power is turned off and the CAN signal is normally inputtedto the EWP controller, and set the EWP to enter a sleep mode when the IGpower is turned off and the CAN signal is not normally inputted to theEWP controller.
 18. The system of claim 17, wherein the EWP is furtherconfigured to perform the sleep mode after a predetermined time haspassed when the EWP is set to enter the sleep mode from the normal mode.19. A computer readable storage medium containing a computer programconfigured to cause an EWP controller to control an electric water pump(EWP) by the following method when read and processed by a computersystem: receiving a controller area network (CAN) signal from an engineelectronic control unit (ECU) to control the EWP through a controllerarea network (CAN); receiving a fail-safe digital signal (FSDS) that isrelated to a fail-safe control function of an engine or the EWP from theECU; and controlling the EWP based on the CAN signal and the fail-safedigital signal.